Sensor misalignment measuring device

ABSTRACT

The present disclosure relates to measuring misalignment between layers of a semiconductor device. In one embodiment, a device includes a first conductive layer; a second conductive layer; one or more first electrodes embedded in the first conductive layer; one or more second electrodes embedded in the second conductive layer; a sensing circuit connected to the one or more first electrodes; and a plurality of time-varying signal sources connected to the one or more second electrodes, wherein the one or more first electrodes and the one or more second electrodes form at least a portion of a bridge structure that exhibits an electrical property that varies as a function of misalignment of the first conductive layer and the second conductive layer in an in-plane direction.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is a continuation of, and claims priority to,U.S. patent application Ser. No. 16/750,650, filed on Jan. 23, 2020, andentitled “IN-PLANE SENSOR MISALIGNMENT MEASURING DEVICE USING CAPACITIVESENSING,” which is a divisional application of, and claims priority to,U.S. patent application Ser. No. 15/783,792, filed on Oct. 13, 2017, andentitled “SENSOR MISALIGNMENT MEASURING DEVICE,” each of which areincorporated by reference in their entirety herein.

BACKGROUND

Certain sensor devices (e.g., accelerometers, gas sensors, etc.) aredesigned to accommodate a given amount of misalignment betweenconductive device layers and/or other component parts of the device. Ifthe design is not implemented correctly, or if the actual misalignmentbetween components exceeds the accommodated amount, performance and/orreliability problems can result. Accordingly, it would be desirable toimplement techniques for measuring misalignment on a fabricated device.

SUMMARY

The following presents a simplified summary of one or more of theembodiments of the present disclosure in order to provide a basicunderstanding the embodiments. This summary is not an extensive overviewof the embodiments described herein. It is intended to neither identifykey or critical elements of the embodiments nor delineate any scope ofembodiments or the claims. This Summary's sole purpose is to presentsome concepts of the embodiments in a simplified form as a prelude tothe more detailed description that is presented later. It will also beappreciated that the detailed description may include additional oralternative embodiments beyond those described in the Summary section.

The present disclosure recognizes and addresses, in at least certainembodiments, the issue of detecting misalignment in a semiconductordevice, e.g., a sensor device. Various semiconductor devices can includemultiple layers formed or otherwise placed onto each other. If thedesign of the device is incorrect, or if the misalignment between layersexceeds a tolerated amount, performance and/or reliability issues canresult. The disclosed systems and methods provide for a misalignmentsensor that can be incorporated into a semiconductor device to enable afast, nondestructive measurement of misalignment. The disclosedmisalignment sensor can be readily integrated with existingsemiconductor structures with minimal additional area or circuits.

In one aspect disclosed herein, a device includes a first conductivelayer, a second conductive layer, one or more first electrodes embeddedin the first conductive layer, one or more second electrodes embedded inthe second conductive layer, a sensing circuit connected to the one ormore first electrodes, and a plurality of time-varying signal sourcesconnected to the one or more second electrodes. The one or more firstelectrodes and the one or more second electrodes forms at least aportion of a bridge structure that exhibits an electrical property thatvaries as a function of misalignment of the first conductive layer andthe second conductive layer in an in-plane direction.

Other embodiments and various examples, scenarios and implementationsare described in more detail below. The following description and thedrawings set forth certain illustrative embodiments of thespecification. These embodiments are indicative, however, of but a fewof the various ways in which the principles of the specification may beemployed. Other advantages and novel features of the embodimentsdescribed will become apparent from the following detailed descriptionof the specification when considered in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a high-level block diagram of a system for measuringmisalignment between respective layers of a semiconductor device inaccordance with one or more embodiments of the disclosure.

FIG. 2 depicts example layer misalignment in a semiconductor device thatcan be detected by the system of FIG. 1.

FIG. 3 is a simplified schematic diagram of a single-ended sensingcircuit with single-ended input sensing that can be utilized by variousembodiments described herein.

FIG. 4 is a cross-sectional diagram of an electrical device structurethat can utilize sensing techniques as shown in FIG. 3.

FIG. 5 is a simplified schematic diagram of a single-ended sensingcircuit with single-ended feedback sensing and gain correction that canbe utilized by various embodiments described herein.

FIG. 6 is a cross-sectional diagram of an electrical device structurethat can utilize sensing techniques as shown in FIG. 5.

FIG. 7 is a simplified schematic diagram of a differential sensingcircuit with single-ended input sensing that can be utilized by variousembodiments described herein.

FIG. 8 is a cross-sectional diagram of an electrical device structurethat can utilize sensing techniques as shown in FIG. 7.

FIG. 9 is a simplified schematic diagram of a differential sensingcircuit with differential feedback sensing that can be utilized byvarious embodiments described herein.

FIGS. 10-11 are cross-sectional diagrams of respective electrical devicestructures that can utilize sensing techniques as shown in FIG. 9.

FIG. 12 is a simplified schematic diagram of a half-bridge sensingcircuit with differential input sensing that can be utilized by variousembodiments described herein.

FIGS. 13-15 are cross-sectional diagrams of respective electrical devicestructures that can utilize sensing techniques as shown in FIG. 12.

FIG. 16 is a simplified schematic diagram of a half-bridge sensingcircuit with differential input sensing and gain correction that can beutilized by various embodiments described herein.

FIG. 17 is a cross-sectional diagram of an electrical device structurethat can utilize sensing techniques as shown in FIG. 16.

FIG. 18 is a simplified schematic diagram of a half-bridge sensingcircuit with differential feedback sensing and gain correction that canbe utilized by various embodiments described herein.

FIG. 19 is a cross-sectional diagram of an electrical device structurethat can utilize sensing techniques as shown in FIG. 18.

FIG. 20 is a simplified schematic diagram of a full-bridge sensingcircuit with differential input sensing that can be utilized by variousembodiments described herein.

FIGS. 21-22 are cross-sectional diagrams of respective electrical devicestructures that can utilize sensing techniques as shown in FIG. 20.

FIG. 23 is a flow diagram of a method for detecting misalignment betweenlayers of a semiconductor device in accordance with one or moreembodiments of the disclosure.

DETAILED DESCRIPTION

The present disclosure recognizes and addresses, in at least certainembodiments, the issue of detecting misalignment in a semiconductordevice. Various semiconductor devices can include multiple layers formedor otherwise placed onto each other. If the design of the semiconductordevice is incorrect, or if the misalignment between layers exceeds atolerated amount, performance and/or reliability issues can result. Thedisclosed systems and methods provide for a misalignment sensor that canbe incorporated into a semiconductor device to enable a fast,nondestructive measurement of misalignment. The disclosed misalignmentsensor can be readily integrated with existing semiconductor structureswith minimal additional area or circuits.

With reference to the drawings, FIG. 1 depicts a system 100 formeasuring misalignment between respective layers of a semiconductordevice in accordance with one or more embodiments of the disclosure. Asillustrated, the system 100 includes a semiconductor device thatincludes a first conductive layer 10, an intermediate layer 20, and asecond conductive layer 30. The layers are formed and/or otherwisepositioned as shown in system 100 such that a first (e.g., top) surfaceof the intermediate layer 20 is situated adjacent to a first (e.g.,bottom) surface of the first conductive layer 10 and a second (e.g.,bottom) surface of the intermediate layer 20 opposite the first surfaceis situated adjacent to a first (e.g., top) surface of the secondconductive layer 30. While the layers 10, 20, 30 shown in system 100 areoriented from top to bottom in a stack configuration, it should beappreciated that the layers 10, 20, 30 of system 100 could be orientedin any other suitable configuration, e.g., the second conductive layer30 could be situated above the intermediate layer 20 and the firstconductive layer 10 could be situated below the intermediate layer 20.Other configurations are also possible.

In various embodiments, the intermediate layer 20 can be either aconductive layer or a nonconductive layer in order to support theparticular sensing method and associated electrical properties utilizedby a given implementation. Respective embodiments utilizing conductiveand nonconductive intermediate layers are described in further detailbelow.

As further shown by FIG. 1, the first conductive layer 10 has embeddedtherein one or more first electrodes 40, and the second conductive layer30 has embedded therein one or more second electrodes 50. While twofirst electrodes 40 and two second electrodes 50 are illustrated in FIG.1, it should be appreciated that each of the conductive layers 10, 30could have embedded therein any suitable number of electrodes. Theelectrical connections between the one or more first electrodes 40 andthe one or more second electrodes 50 form a suitable network (e.g., asingle-ended network, a half bridge, or a full bridge) that exhibits anelectrical property (e.g., capacitance, electrical charge, conductance,etc.) that varies as a function of misalignment of the first conductivelayer 10 and the second conductive layer 30 in an in-plane direction.

In an aspect, the electrodes 40, 50 are electrically coupled to asensing circuit 60, which can be an electrical circuit and/or any othersuitable means for measuring the electrical property of the electrodes40, 50. The sensing circuit 60, in various embodiments, can be asingle-ended sensing circuit, a differential sensing circuit, and/or anyother component(s) suitable for measuring the electrical property of thenetwork formed by one or more of the electrodes 40, 50 or theirrespective associated layers 10, 30.

In some embodiments, system 100 can be, or incorporate the functionalityof at least a portion of a sensor device such as an accelerometer, a gassensor, a temperature sensor, a pressure sensor, or the like. In anaspect, a sensor device can be composed of one or more layers 10, 20,30, as shown in FIG. 1 and described above, that are bonded togetheraccording to one or more semiconductor fabrication techniques. Thecomposition of the layers 10, 20, 30, for a particular sensor device canvary based on the desired functionality of the device and/or otherfactors. In one example, the first conductive layer 10 can be a layer ofa micro-electro-mechanical system (MEMS) wafer, and the secondconductive layer 30 can be a layer of a complementarymetal-oxide-semiconductor (CMOS) wafer, or vice versa. Other layer typescould also be employed.

In an aspect, a sensor device composed of layers 10, 20, 30 can bedesigned to accommodate a given amount of misalignment. Turning to FIG.2, cross-sectional diagrams 200 and 202 illustrate a semiconductordevice having layers 10, 20, 30, where layers 10 and 30 are subject to amisalignment tolerance 210. In one non-limiting example, themisalignment tolerance 210 shown in diagram 200 corresponds to a maximummisalignment that results in respective features of layers 10 and 30being aligned to each other to within an acceptable degree. Forinstance, cross-sectional diagram 202 in FIG. 2 illustrates a scenarioin which a given component of the first conductive layer 10 is alignedwith a corresponding component of the second conductive layer 30 at anedge of the two components such that any further misalignment betweenthe conductive layers 10, 30 would result in the components no longerbeing fully aligned. It should be appreciated, however, that thepreceding is merely a non-limiting example of a misalignment tolerance210 that could be used and that other misalignment tolerances are alsopossible.

Misalignment between layers of a semiconductor device as shown bydiagrams 200, 202 can occur due to imprecision in fabrication processesand/or other factors. Prior to fabrication of a given semiconductordevice, the allowable misalignment can be specified with the foundryand/or other fabrication facility. If the design is not done correctly,or if the actual misalignment of the device as fabricated exceeds thisspecification, performance and/or reliability problems can result.However, conventional techniques for measuring misalignment on afabricated device can be time-consuming and/or costly. This means thatif performance or reliability problems are observed, it can be difficultto confirm or rule out misalignment as a possible cause. This also meansthat it can be difficult to monitor the foundry's compliance with themisalignment specification.

In an aspect, the electrodes 40, 50 and the sensing circuit 60 shown inFIG. 1 operate as a misalignment sensor, e.g., a structure that can beincluded on a device die to enable a fast, nondestructive measurement ofmisalignment. This structure, according to various embodiments describedbelow, can be readily integrated with semiconductor devices such assensors with minimal associated MEMS area overhead, additional CMOScircuits, or the like.

In an aspect, a semiconductor misalignment sensor as described hereincan be implemented for a semiconductor structure such as the structureshown by diagrams 200, 202 in FIG. 2. In one example, components of themisalignment sensor can include a MEMS structure including three piecesof silicon arranged in a side-by-side manner and connected to respectivenodes, e.g., as shown by the structure of layer 10 in diagrams 200, 202.The misalignment sensor can further include and/or be associated with aCMOS structure including one or more electrodes (e.g., 1 or 2electrodes) arranged underneath the MEMS structure, e.g., as shown bythe structure of layer 30 in diagrams 200, 202. In this configuration,the structure can function by measuring an electrical property (e.g.,capacitance, electrical charge, electrical conductance, etc.) betweenthe CMOS structure and the MEMS structure. An electrical input (e.g., aconstant voltage, an oscillating voltage provided as a sine wave, squarewave, or the like, etc.) is applied to one or more nodes associated withthe sensor, and the current or voltage output is measured at one or moredifferent nodes.

While the above description and various ones of the embodimentsdescribed herein utilize a MEMS layer and a CMOS layer, it should beappreciated that other configurations could also be used. For instance,a misalignment sensor as described herein could be utilized to measuremisalignment between two or more CMOS layers (e.g., CMOS interconnectlayers), two or more MEMS layers, and/or any other combination of CMOS,MEMS, and/or other layers that can be implemented via a semiconductordevice.

Turning now to FIGS. 3-22, respective configurations of a misalignmentsensor that can be implemented according to one or more embodimentsdescribed herein are illustrated. It should be appreciated, however,that the configurations depicted by FIGS. 3-22 comprise merely anon-exhaustive listing of sensor configurations that can be utilized andthat other configurations are also possible. Further, while respectiveones of FIGS. 3-22 are illustrated in the context of specific layerconfigurations and/or types, it should additionally be appreciated that,unless stated otherwise, similar configurations to those illustratedcould be employed for other layer types and/or configurations withoutdeparting from the scope of the embodiments described herein.

In the following descriptions, respective embodiments are illustratedand described with reference first to a simplified schematic diagram ofthe sensing techniques used by the respective embodiments followed byone or more cross-sectional diagrams that can be utilized to implement asensing circuit as illustrated in the schematic diagram. It should beappreciated, however, that the cross-sectional diagrams shown anddescribed herein are merely examples of structures that can be utilizedand that other structures could also be used.

With reference first to FIG. 3, a simplified schematic diagram of asingle-ended sensing circuit 300 with single-ended input sensing isprovided. As shown in FIG. 3 and the figures that follow, the arrowsrepresent an impedance (e.g., overlap) change due to misalignment. Here,an applied input voltage results in an output voltage. The outputvoltage is used to calculate impedance Zi, which is used in turn tocalculate the extent of misalignment, if any, between the layers of theassociated device, e.g., layers 10 and 30 as shown in FIG. 1.

FIG. 4 illustrates a system 400 for detecting misalignment between afirst conductive layer (e.g., a MEMS layer, etc.) including an electrode401 and a second conductive layer (e.g., a CMOS layer, etc.) includingelectrodes 411, 412 using the sensing techniques of circuit 300 withgain correction. A nonconductive material (not shown), such as an airgap or a dielectric material, is positioned between the two layers. Inan aspect, electrode 401 of the first layer can be a first electrode 40as shown in FIG. 1. Further, electrodes 411, 412 of the second layer canbe respective second electrodes 50 as illustrated in FIG. 1.

As shown by FIG. 4, electrode 411 can be connected to a voltage source451, and a resulting electrical charge at electrode 401 can be measuredby a single-ended sensing circuit 461. The resulting electrical chargecan, in turn, be used to calculate misalignment between layers of thesystem 400, e.g., the first layer including electrode 401 and the secondlayer including electrodes 411, 412. While FIG. 4 illustrates thatelectrode 411 and voltage source 451 are connected via a switch, itshould be appreciated that other switching configurations could also beused.

In another aspect, each of the impedances of system 400 utilizes theintermediate layer 20 of FIG. 1 (not shown in FIG. 4), so that variationof the thickness of the intermediate layer affects the impedancesequally. Thus, the non-sensitive feedback impedance Z₂ scales the gainof the sensing circuit (i.e., the ratio between the output voltage ofsensing circuit 461 and voltage source 451) to be proportional to thesensed impedances Z₁ and Z₂. This makes the voltage output of thesensing circuit independent of the thickness of the intermediate layer.

Turning next to FIG. 5, a simplified schematic diagram of a single-endedsensing circuit 500 with single-ended feedback sensing is provided.Here, an impedance Z₁ is obtained by applying an input voltage, and theimpedance Z₁ is used to calculate the extent of misalignment, if any,between the layers of the associated device, e.g., layers 10 and 30 asshown in FIG. 1. In an aspect, the circuit 500 can operate in a similarmanner to the circuit 300 shown in FIG. 3 with the exception that theimpedance Z₁ is connected in feedback around the sensing circuit.

FIG. 6 illustrates a system 600 for detecting misalignment between afirst conductive layer including an electrode 601 and a secondconductive layer including electrodes 611, 612 using the sensingtechniques of circuit 500. Similar to system 400, a nonconductivematerial (not shown), such as an air gap or a dielectric material, ispositioned between the two layers.

As shown by FIG. 6, electrode 612 can be connected to a voltage source651, and a resulting electrical charge at electrode 601 can be measuredby a single-ended sensing circuit 661. The resulting electrical chargecan, in turn, be used to calculate misalignment between layers of thesystem 400, e.g., the first layer including electrode 601 and the secondlayer including electrodes 611, 612. While FIG. 6 illustrates thatelectrode 612 and voltage source 651 are connected via a switch, itshould be appreciated that other switching configurations could also beused. In another aspect, the system 600 exhibits gain correction in asimilar manner to that described above with respect to system 400.

As further illustrated in the drawings, FIG. 7 is a simplified schematicdiagram of a differential sensing circuit 700 with single-ended inputsensing. Here, the difference of impedances Z₁ and Z₂ is used tocalculate the extent of misalignment, if any, between the layers of theassociated device, e.g., layers 10 and 30 as shown in FIG. 1.

Turning to FIG. 8, a system 800 for detecting misalignment betweenconductive layers of an electrical device using the sensing techniquesof circuit 700 is illustrated. Here, the semiconductor device includes afirst conductive layer (e.g., a MEMS layer, etc.) including twoelectrodes 802, 804 and a second conductive layer (e.g., a CMOS layer,etc.) including a single electrode 812. An intermediate layer 20composed of a nonconductive material (not shown), such as an air gap ora dielectric material, is positioned between the two layers.

As shown by system 800, electrodes 802, 804 can be connected viaswitches 820, 822 to respectively corresponding time-varying voltagesources 830, 832. In an aspect, the voltage provided by voltage sources830, 832 can differ according to one or more properties, such asamplitude, phase, or the like. In the example shown by FIG. 8, voltagesources 830, 832 produce respective square waves having opposite phases,e.g., differing by 180 degrees. Other configurations could also be used.

In a similar manner to the embodiments described above, the voltagesources 830, 832 cause an amount of electrical charge to be storedbetween the electrodes 802, 804 of the first layer and electrode 812 ofthe second layer that is proportional to misalignment between the firstlayer and the second layer in an in-plane direction. Electrode 812 isfurther electrically connected to a single-ended sensing circuit 840,which measures the differential capacitance of the half-bridge structurecorresponding to electrodes 802, 804, 812 and/or the associatedelectrical charge to determine an extent of misalignment between thelayers of the semiconductor device. In one example, alternativeswitching configurations to that shown in FIG. 8 could be used. Forinstance, electrode 812 could be connected to sensing circuit 840 via aswitch in addition to, or in place of, switches 820, 822.

Turning next to FIG. 9, a simplified schematic diagram of a differentialsensing circuit 900 with differential feedback sensing is provided. Asshown by FIG. 9, a source impedance Z_(s) is present in the circuit 900,which need not be part of the MEMS structure and need not be used by thesensing circuit for misalignment measurement.

Turning to FIG. 10, illustrated is a system 1000 for detectingmisalignment between a first conductive layer (e.g., a MEMS layer, etc.)including electrodes 1002, 1004 and a second conductive layer (e.g., aCMOS layer, etc.) including electrodes 1022, 1024 using the sensingtechniques of circuit 1000 in a resistive configuration. In an aspect, aconductive intermediate layer 1010 is positioned between the twoconductive layers associated with electrodes 1002, 1004, 1022, 1024. Asfurther shown by FIG. 10, the source impedance Z_(s) in circuit 900 isrepresented by resistors R_(s). In an embodiment, the conductance of theintermediate layer 1010 may be substantially greater than theconductances of electrodes 1002, 1004, 1022, 1024. In anotherembodiment, the conductance of the intermediate layer 1010 may besubstantially less than the conductances of electrodes 1002, 1004, 1022,1024. Other configurations are also possible.

As further shown by system 1000, electrodes 1002, 1004 can be connectedvia switches to respective poles of a voltage source 1030. While thevoltage source 1030 shown in FIG. 10 is a DC voltage source, atime-varying voltage source or other suitable voltage source could beused. When engaged, the voltage source 1030 causes an amount ofdifferential electrical current in the intermediate layer 1010 betweenthe respective electrodes 1002, 1004 of the first layer and electrodes1022, 1024 of the second layer. In an aspect, the amount of resultingdifferential electrical conductance is proportional or otherwise relatedto misalignment between the first layer and the second layer in anin-plane direction. In an aspect, electrodes 1002, 1004 are furtherelectrically connected to a differential sensing circuit 1040, whichmeasures the differential electrical current of the half-bridgestructure to determine an extent of misalignment between the layers ofthe semiconductor device. As further shown by system 1000, thedifferential electrical conductance proportional to misalignment isconnected in the feedback position of the sensing circuit 1040.

System 1100 in FIG. 11 illustrates an alternative configuration tosystem 1000 in an embodiment having two electrodes 1102, 1104 in thefirst conductive layer and two electrodes 1022, 1024 in the secondconductive layer. In contrast to system 1000, system 1100 utilizescapacitive sensing to determine an extent of misalignment, if any,between the first and second conductive layers. As such, a nonconductivelayer, such as an air gap or the like, is positioned between the twoconductive layers, and time-varying input voltages 1130, 1132 arerespectively applied to electrodes 1122, 1124. A differential sensingcircuit is electrically connected to electrodes 1102, 1104 of the secondconductive layer, which function to determine the extent of misalignmentbetween the first and second conductive layers in an in-plane directionbased on a sensed differential capacitance.

Turning next to FIG. 12, a simplified schematic diagram of a half-bridgesensing circuit 1200 with differential input sensing is illustrated. Thedifference of the respective impedances Z₁ and Z₂, can be observed atthe sensing circuit and used to calculate the misalignment betweenlayers of the structure.

FIG. 13 illustrates a system 1300 for detecting misalignment between afirst conductive layer (e.g., a MEMS layer, etc.) including electrodes1302, 1304, 1306, and a second conductive layer (e.g., a CMOS layer,etc.) including an electrode 1312, according to the sensing techniquesof circuit 1200. A nonconductive material (not shown), such as an airgap or a dielectric material, is positioned between the two layers.Here, electrodes 1302 and 1304 of the first layer are associated withsensing nodes, and electrode 1306 of the first layer can in someembodiments be utilized as a secondary sensing node as described below.Alternatively, the first conductive layer may include only electrodes1302 and 1304.

As further shown by system 1300, electrode 1312 can be connected via aswitch 1320 to a time-varying voltage source 1322 (e.g., a square wavevoltage generator, etc.). When engaged, the voltage source 1322 causesan amount of electrical charge to be stored between electrodes 1302,1304 of the first layer and electrode 1312 of the second layer. In anaspect, the difference of the respective amounts of charge isproportional to misalignment between the first layer and the secondlayer in an in-plane direction. This stored electrical charge differencecorresponds to a capacitance difference between electrodes 1302, 1304 ofthe first layer and electrode 1312 of the second layer, which is shownin FIG. 13 as equivalent capacitors for clarity of illustration. In thisway, electrodes 1302, 1304, 1312 operatively form a capacitivehalf-bridge structure having a differential capacitance proportional tothe misalignment of the layers of the underlying semiconductor device.As additionally shown by system 1300, electrodes 1302, 1304 areelectrically connected to a differential sensing circuit 1330, whichmeasures the differential capacitance of the half-bridge structureand/or the associated electrical charge to determine an extent ofmisalignment between the layers of the semiconductor device.

In an aspect, electrode 1306 can be utilized to calculate a specificcapacitance (i.e., capacitance per unit area) associated with the firstand second conductive layers, from which the approximate thickness ofthe intermediate layer between the first and second conductive layerscan be derived. By way of example, electrode 1306 can be connected to asingle-ended sensing circuit (not shown) that is different from sensingcircuit 1330. The output of the single-ended sensing circuit resultingfrom the procedure described above can be proportional or inverselyproportional to the thickness of the intermediate layer, which can beused in combination with the measured electrical charge to determine thecapacitance between the first and second layers.

While FIG. 13 illustrates that electrode 1312 and voltage source 1322are connected via a switch 1320, it should be appreciated that otherswitching configurations could also be used. For instance, therespective connections between sensing electrodes 1302, 1304 and thesensing circuit 1330 could be controlled by similar switching mechanismsin addition to, or in place of, switch 1320 connecting electrode 1312 tovoltage source 1322.

With reference next to FIG. 14, illustrated is another system 1400 fordetecting misalignment between conductive layers of a semiconductordevice, here a first conductive layer (e.g., a MEMS layer, etc.)including an electrode 1402 and a second conductive layer (e.g., a CMOSlayer, etc.) including two electrodes 1412, 1414, using the sensingtechniques of circuit 1200. Similar to system 1300, a nonconductivematerial (not shown), such as an air gap or a dielectric material, ispositioned between the two layers.

As further shown by system 1400, electrode 1402 can be connected to atime-varying voltage source 1420 (e.g., a square wave voltage generator,etc.), which causes an amount of electrical charge to be stored betweenelectrode 1402 of the first layer and electrodes 1410, 1412 of thesecond layer. Similarly to system 1300 described above, the differenceof the respective amounts of charge can be proportional to misalignmentbetween the first layer and the second layer in an in-plane direction,enabling electrodes 1402, 1412, 1414 to operate as a capacitivehalf-bridge structure in a similar manner to system 1300. Asadditionally shown by system 1400, electrodes 1412, 1414 of the secondlayer can be electrically connected via respective switches 1432, 1434to a differential sensing circuit 1440, which measures the capacitanceof the half-bridge structure and/or the associated electrical charge todetermine an extent of misalignment between the layers of thesemiconductor device.

While FIG. 14 illustrates that electrodes 1412, 1414 are connected tosensing circuit 1440 via respective switches 1432, 1434, it should beappreciated that other switching configurations could also be used. Forinstance, electrode 1402 could be connected to voltage source 1420 via aswitch in addition to, or in place of, switches 1432, 1434.

With reference next to FIG. 15, illustrated is a system 1500 fordetecting misalignment between a first conductive layer (e.g., a MEMSlayer, etc.) including electrodes 1502, 1504, 1506, and a secondconductive layer (e.g., a CMOS layer, etc.) including an electrode 1512using a resistive half-bridge structure according to the sensingtechniques of circuit 1200. A conductive intermediate layer 1510 ispositioned between the two conductive layers associated with electrodes1502, 1504, 1506, 1512.

As further shown by system 1500, electrode 1512 can be connected via aswitch 1520 to a voltage source 1522. While the voltage source 1522shown in FIG. 15 is a DC voltage source, other voltage sources could beused, such as the time-varying voltage source 1522 described above withrespect to FIGS. 13-14. When engaged, the voltage source 1522 causes anamount of differential electrical current in the intermediate layer 1510between electrodes 1502, 1504 of the first layer and electrode 1512 ofthe second layer. In an aspect, the resulting amount of differentialelectrical conductance is proportional to misalignment between the firstlayer and the second layer in an in-plane direction. In an aspect,electrodes 1502, 1504 are electrically connected to a differentialsensing circuit 1530, which measures the differential conductance of thehalf-bridge structure to determine an extent of misalignment between thelayers of the semiconductor device.

Referring next to FIG. 16, a half-bridge sensing circuit 1600 withdifferential input sensing and gain correction is illustrated. In anaspect, each of the impedances of circuit 1600 utilize the intermediatelayer, so that variation of the thickness of the intermediate layeraffects the impedances equally. Thus, the non-sensitive feedbackimpedances Z_(N1) and Z_(N2) scale the gain of the sensing circuit to beproportional to the sensed impedances Z₁ and Z₂. This makes the voltageoutput of the sensing circuit independent of the thickness of theintermediate layer.

FIG. 17 illustrates a system 1700 for detecting misalignment between afirst conductive layer including electrodes 1701, 1702, and a secondconductive layer including electrodes 1711, 1712, 1713 according to thesensing techniques of circuit 1600. As shown by FIG. 17, electrode 1711can be connected to a voltage source 1751, and a resulting electricalcharge at electrodes 1701, 1702 can be measured by a differentialsensing circuit 1761.

Turning to FIG. 18, a half-bridge sensing circuit 1800 with differentialfeedback sensing and gain correction is illustrated. In an aspect,circuit 1800 can employ a similar half-bridge differential sensingcircuit with gain correction to that shown by circuit 1600, whichdiffers from circuit 1600 in that the positions of impedances Z₁ and Z₂and those of ZN1 and ZN2 are interchanged.

FIG. 19 illustrates a system 1900 for detecting misalignment between afirst conductive layer including electrodes 1901, 1902, and a secondconductive layer including electrodes 1911, 1912, 1913 according to thesensing techniques of circuit 1800. As shown by FIG. 19, electrode 1911can be connected to a voltage source 1951, and a resulting electricalcharge at electrodes 1911, 1912 can be measured by a differentialsensing circuit 1961.

Referring next to FIG. 20, a simplified schematic diagram of afull-bridge sensing circuit 2000 with differential input sensing isprovided. In an aspect, the full-bridge structure can be constructedfrom two half-bridge structures according to one or more embodimentsdescribed above. The half-bridge structures, in turn, can correspond torespective portions of a semiconductor device and/or its respectiveconductive layers. For instance, a first half-bridge structure couldcorrespond to a first sensor or other device or circuit implemented on asemiconductor chip while the second half-bridge could correspond to asecond, different device or circuit. Other configurations are alsopossible. As further illustrated in FIG. 20, the first half-bridgecorresponds to impedances Z₁ and Z₂, and the second half-bridgecorresponds to impedances Z3 and Z4.

Referring next to FIG. 21, a system 2100 for measuring misalignment of asemiconductor device according to the sensing techniques of circuit 2000includes two conductive layers that are physically or electricallyseparated into two distinct portions. Electrodes 2102 and 2104 areassociated with a first portion of the first conductive layer, andelectrode 2112 is associated with a first portion of the secondconductive layer. Similarly, electrodes 2122 and 2124 are associatedwith a second portion of the first conductive layer, and electrode 2132is associated with a second portion of the second conductive layer. Asfurther shown in FIG. 21, a nonconductive intermediate layer 20 ispositioned between the first and second conductive layers, which can becomposed of an air gap or a dielectric material in a similar manner tothat described above with respect to FIG. 8.

In an aspect, electrodes 2102, 2104 are connected to a firsttime-varying voltage source 2140 via a first switch 2150. Similarly,electrodes 2122, 2124 are connected to a second time-varying voltagesource 2142 via a second switch 2152. For instance, as shown in FIG. 21,voltage sources 2140, 2142 are two distinct square-wave generatorshaving opposite phases. Other configurations, wave types, etc., couldalso be used.

In a similar manner to that described above, the voltage source 2140causes a differential amount of electrical charge to be stored betweenelectrodes 2102, 2104 of the first layer and electrode 2112 of thesecond layer. Similarly, the voltage source 2142 causes a differentialamount of electrical charge to be stored between electrodes 2122, 2124of the first layer and electrode 2132 of the second layer. Electrodes2102, 2124 of the first layer are connected to a first input of adifferential sensing circuit 2160, and electrodes 2104, 2122 of thefirst layer are connected to a second input of differential sensingcircuit 2160. Differential sensing circuit 2160, in turn, determines anextent of misalignment between the first and second conductive layers,and/or respective component electrodes, sensing nodes, or other featuresassociated with the conductive layers, as a function of the storedelectrical charge and/or its associated capacitance.

System 2200 in FIG. 22 illustrates an alternative configuration tosystem 2100 in an embodiment in which the first portion of thesemiconductor device includes a single electrode 2202 in the firstconductive layer and two electrodes 2212, 2214 in the second conductivelayer, and the second portion of the semiconductor device includes asingle electrode 2222 in the first conductive layer and two electrodes2232, 2234 in the second conductive layer. Similar to system 2100 inFIG. 21, a nonconductive intermediate layer 20 is positioned between thefirst and second conductive layers of system 2200, which can be composedof an air gap or a dielectric material in a similar manner to thatdescribed above with respect to FIG. 8. As shown by FIG. 22, electrodes2212, 2234 of the second layer are connected to a first time-varyingvoltage 2240 via a first switch 2250, and electrodes 2214, 2232 of thesecond layer are connected to a second time-varying voltage 2242 via asecond switch 2252. The time-varying voltages 2240, 2242 can vary inphase and/or other characteristics in a similar manner to thetime-varying voltages 640, 642, and/or in any other suitable manner. Asfurther shown by system 2200, electrodes 2202, 2222 of the first layerare connected to respective inputs of a differential sensing circuit2260, which determines an extent of misalignment between the first andsecond conductive layers, and/or respective component electrodes,sensing nodes, or other features associated with the conductive layers,as a function of the stored electrical charge and/or its associatedcapacitance.

FIG. 23 presents a flowchart of an example method 2300 for detectingmisalignment between layers of a semiconductor device in accordance withone or more embodiments of the disclosure. At block 2302, an inputvoltage is applied to respective ones of one or more first electrodes(e.g., first electrodes 40) associated with a first conductive layer(e.g., conductive layer 10) of a semiconductor device.

At 2304, in response to applying the input voltage at 2302, anelectrical property of one or more second electrodes (e.g., secondelectrodes 50) associated with a second conductive layer (e.g.,conductive layer 30) of the semiconductor device is sensed (e.g., via asensing circuit 60). The electrical property sensed at 2304 can include,but is not limited to, electrical charge, electrical conductance,capacitance, etc. In an aspect, the electrical property can be sensed byfirst measuring an output voltage associated with the one or more secondelectrodes and subsequently determining the electrical property from themeasured output voltage.

At 2306, a misalignment between the first and second conductive layersof the semiconductor device, e.g., in an in-plane direction, iscalculated as a function of the electrical property sensed at 2304.

In the present specification, the term “or” is intended to mean aninclusive “or” rather than an exclusive “or.” That is, unless specifiedotherwise, or clear from context, “X employs A or B” is intended to meanany of the natural inclusive permutations. That is, if X employs A; Xemploys B; or X employs both A and B, then “X employs A or B” issatisfied under any of the foregoing instances. Moreover, articles “a”and “an” as used in this specification and annexed drawings shouldgenerally be construed to mean “one or more” unless specified otherwiseor clear from context to be directed to a singular form.

In addition, the terms “example” and “such as” are utilized herein tomean serving as an instance or illustration. Any embodiment or designdescribed herein as an “example” or referred to in connection with a“such as” clause is not necessarily to be construed as preferred oradvantageous over other embodiments or designs. Rather, use of the terms“example” or “such as” is intended to present concepts in a concretefashion. The terms “first,” “second,” “third,” and so forth, as used inthe claims and description, unless otherwise clear by context, is forclarity only and doesn't necessarily indicate or imply any order intime.

What has been described above includes examples of one or moreembodiments of the disclosure. It is, of course, not possible todescribe every conceivable combination of components or methodologiesfor purposes of describing these examples, and it can be recognized thatmany further combinations and permutations of the present embodimentsare possible. Accordingly, the embodiments disclosed and/or claimedherein are intended to embrace all such alterations, modifications andvariations that fall within the spirit and scope of the detaileddescription and the appended claims. Furthermore, to the extent that theterm “includes” is used in either the detailed description or theclaims, such term is intended to be inclusive in a manner similar to theterm “comprising” as “comprising” is interpreted when employed as atransitional word in a claim.

What is claimed is:
 1. A device, comprising: a first conductive layer; asecond conductive layer; one or more first electrodes embedded in thefirst conductive layer; two or more second electrodes embedded in thesecond conductive layer; a sensing circuit connected to each of the oneor more first electrodes and at least one of the two or more secondelectrodes; and a voltage source connected to at least one electrode ofthe two or more second electrodes, wherein the one or more firstelectrodes and the two or more second electrodes form at least a portionof a bridge structure that exhibits an electrical property as measuredby the sensing circuit in response to application of the voltage sourceconnected to the at least one electrode of the two or more secondelectrodes, and wherein the electrical property varies as a function ofmisalignment of the first conductive layer and the second conductivelayer in an in-plane direction.
 2. The device of claim 1, furthercomprising an intermediate layer having a first surface situatedadjacent to a first surface of the first conductive layer and a secondsurface opposite to the first surface of the intermediate layer, whereinthe second conductive layer has a first surface situated adjacent to thesecond surface of the intermediate layer.
 3. The device of claim 2,wherein the intermediate layer is a nonconductive layer.
 4. The deviceof claim 3, wherein the intermediate layer comprises an air gap.
 5. Thedevice of claim 3, wherein the intermediate layer comprises a dielectricmaterial.
 6. The device of claim 3, wherein: the one or more firstelectrodes comprise one first electrode; the two or more secondelectrodes comprise two second electrodes; and the first electrode andthe second electrodes form a capacitive half-bridge structure thatexhibits an electrical charge that varies as the function of themisalignment of the first conductive layer and the second conductivelayer in the in-plane direction.
 7. The device of claim 6, wherein: thevoltage source is a time-varying voltage source connected to a firstelectrode of the two second electrodes; and the sensing circuit is asingle-ended sensing circuit.
 8. The device of claim 7, wherein: thefirst electrode is connected to an input position of the single-endedsensing circuit; and a second electrode of the two second electrodes,distinct from the first electrode of the two second electrodes, isconnected to a feedback position of the single-ended sensing circuit. 9.The device of claim 3, wherein: the one or more first electrodescomprise two first electrodes; the two or more second electrodescomprise two second electrodes; and the first electrodes and the secondelectrodes form a capacitive half-bridge structure that exhibits anelectrical charge that varies as the function of the misalignment of thefirst conductive layer and the second conductive layer in the in-planedirection.
 10. The device of claim 9, wherein: the voltage source is afirst time-varying voltage source connected to a first electrode of thetwo second electrodes; the device further comprises a secondtime-varying voltage source connected to a second electrode of the twosecond electrodes that is distinct from the first electrode of the twosecond electrodes; and the sensing circuit is a differential sensingcircuit.
 11. The device of claim 10, wherein: the two first electrodesare connected to respective feedback positions of the differentialsensing circuit; and the two second electrodes are connected torespective input positions of the differential sensing circuit.
 12. Thedevice of claim 3, wherein: the one or more first electrodes comprisetwo first electrodes; the two or more second electrodes comprise threesecond electrodes; and the first electrodes and the second electrodesform a capacitive half-bridge structure that exhibits an electricalcharge that varies as the function of the misalignment of the firstconductive layer and the second conductive layer in the in-planedirection.
 13. The device of claim 12, wherein: the voltage source is atime-varying voltage source connected to a first electrode of the threesecond electrodes; and the sensing circuit is a differential sensingcircuit.
 14. The device of claim 13, wherein: the first electrodes areconnected to respective input positions of the differential sensingcircuit; a second electrode of the three second electrodes, distinctfrom the first electrode of the three second electrodes, is connected toa feedback position of the differential sensing circuit; and a thirdelectrode of the three second electrodes, distinct from the firstelectrode of the three second electrodes and the second electrode of thethree second electrodes, is connected to the feedback position of thedifferential sensing circuit.
 15. The device of claim 13, wherein: thefirst electrodes are connected to respective feedback positions of thedifferential sensing circuit; a second electrode of the three secondelectrodes, distinct from the first electrode of the three secondelectrodes, is connected to an input position of the differentialsensing circuit; and a third electrode of the three second electrodes,distinct from the first electrode of the three second electrodes and thesecond electrode of the three second electrodes, is connected to theinput position of the differential sensing circuit.
 16. The device ofclaim 2, wherein: the intermediate layer is a conductive layer; the oneor more first electrodes comprise two first electrodes; the two or moresecond electrodes comprise two second electrodes; and the firstelectrodes and the second electrodes form a resistive half-bridgestructure that exhibits an electrical conductance that varies as thefunction of the misalignment of the first conductive layer and thesecond conductive layer in the in-plane direction.
 17. The device ofclaim 16, wherein: the voltage source is a direct current voltage sourcehaving a first pole connected to a first electrode of the two firstelectrodes and a second pole connected to a second electrode of the twofirst electrodes that is distinct from the first electrode of the twofirst electrodes; and the sensing circuit is a differential sensingcircuit.
 18. The device of claim 17, wherein: the two first electrodesare connected to respective input positions of the differential sensingcircuit; and the two second electrodes are connected to respectivefeedback positions of the differential sensing circuit.
 19. The deviceof claim 1, wherein at least one of the first conductive layer or thesecond conductive layer is a micro-electro-mechanical systems (MEMS)layer.
 20. The device of claim 1, wherein at least one of the firstconductive layer or the second conductive layer is a complementarymetal-oxide-semiconductor (CMOS) die layer associated with the device.